Control device for heating apparatus



Dec. 20, 1932. w, EGGLESTQN I 1,891,758

CONTROL DEVICE FOR HEATING APPARATUS Filed Sept. 22, 1926 7 432 INVENTOR.

BY .7 I a, W

'ZJ ATTORNEY.

Patented Dec. 20, 1932 UNITED STATES PATENT, OFFICE LEWIS W. EGGLESTON, 01 CLARENCE TOWNSHIP, ERIE COUNTY, NEW YORK, ASSIGNOR TO AMERICAN RADIATOR COMPANY, OF NEW YORK,

JERSEY N. 'Y., A CORPORATION OF NEW CONTROL DEVICE FOR HEATING APPARATUS v Application fl led September 22, 1926; Serial No. 187,116.

level in a boiler, to regulate the rate of combustion in the heating apparatus.

While the invention is capable of wlde use for the control of combustion in a heating apparatus, it will be found particularly useful for controlling the combustion of an oil burner applied to a heating apparatus. For

example, it may be employed to control a.

supply of oil, or a supply of air and oil, to an oil burner, and to stop such supply when the water level in the boiler falls below a predetermined point of safety. a

The invention may also include a, device not only for control in response to a variation of liquid level, but which'may also respond to variations of pressure in the heating apparatus, for example, steam pressure in a boiler, so as to control or regulate combustion in the heating apparatus.

The invention consists in the improvements to be more fullydescribed hereinafter, and the novelty of which will be particularly pointed out and distinctly claimed.

In the accompanying drawing I have fully and clearly illustrated a preferred embodiment of my invention, and in the drawing Fig. 1 is a vertical central sectional View showing certaln of the parts in elevation;

Fig. 2 is a section on the line 2-2 of Fig.

' 1, and

'a float chamber 2 with a hollow cylindrical column 3 communicating therewith and ex- Fig. 3 is a detail planiview of a lever member.

Referring to the drawing by characters of reference, 1 design ates a hollow casing having tending vertically upward therefrom. At its lower end the chamber 2 is provided with av threaded nipple 4 adapted to be connected by a suitable pipe. not shown. with the watercontaining space of a boiler at a pointbelow the normal liquid level in the latter. At the head of the column 3 is a nipple 5 adapted to be conuected by a pipe, not shown, to the liquid-containing'space in the boiler at a point The'column 3 may be provided with upper and lower threaded nipples 6, 7, to which may be attached the upper and lower connections of any well known form of gaugeglass, not shown, to indicate visually the liquid level within the hollow casing and the boiler.

The. floatchamber 2 is provided at one side with a flange orhollow extension 8 which opens into and receives a substantially L- shaped hollow fitting 11 with a flange 9. Between the flanges 8 and 9 is a gasket 8 which efi'ectively seals the joint against leakage. Bolts 10, preferably four in number, pass through flange 9 into threaded sockets in flange 8 to fasten said fitting to the chamber 2. The upturned portion or extension 12 of fitting 11 has bolted thereto a flange 13 on the lower end of a hollow couplingimember 14. The coupling member 14 is provided with spaced depending ears 15, which are adapted to extend downwardly within the portion 12 of fitting 11 and which carry a cross-pin 16. 1 I

Upon the pin 16 is mounted a combined rocking and thrust element, preferably in the form of a bar or rod 17, which is provided'atia point intermediate its ends with. a longitudinal slot 18 to receive said pin 16 upon which the rod 17 may fulcrum. The slot is made of a width substantially the same as the diameter of said pin, but said slot is of a greater length than the diameter of said pin 16. The element 17 may not only rock on the pin 16 but is also capable of a sliding or' reciprocating movement thereon, limited by the end walls of the slot 18. Near its-lowerend the rod 17 is formed with a circumferential abutment, (preferably in the form of a shoulder 19. An annular. plate or head 20 having a central opening 20 is positioned on rod 17 and is held thereon by the like, a float 26, which is located in thefloat chamber 2 formed by the casing 1. It

will be seen that the float will be responsive to variations of liquid level within the chamher 2, and when moved will 0 erate through the arm 24 to rock the rod 1 upon its fulcrum 16. 1

Hermetically sealed, as at 27, to the edge of the plate 20, is the lower end of a. dia

phragm, preferably of metal, and in the form of a cylindrical corrugated expansible-collapsible element or bellows 28. The upper end of the element 28 is also hermetically sealed, as at 29, to the inner edge of an annular plate 30, the outer edgeportion of which is clamped, as at 31, in a recess 12" in extension 12 and between the extension 12 and flange 13 heretofore described. The sealing means between the bellows 28 and the plates and 30 is preferably solder, but any suitable substance may be used. A fluid-tight joint is effected at 31, so that said bellows or diaphragm acts as a fluid-tight joint or packing closing the opening about the rod 17 and through the upturned portion of fittingll. It will also be seen that the diaphragm 28 and the head 20 are exposed to fluid pressure which may exist within the system which includes chamber 2 and the fitting 11, and will respond to such pressure to move the rod 17 upwardly with pin 16 riding in slot 18, the response to fluid pressure being controlled or regulated by means to be described hereinafter.

At its upper end the rod 17 acts upon a suitable thrust member 39 in order to trans mit the motion initiated by movement of the float or by fluid pressure on the bellows, to a device controlled or operated thereby to effect acontrol at a remote point. For this purpose the upper end of the rod 17 is provided with a transverse axial open slot 32, which receives and holds a connecting plate 33 having an intermediate transverse edge 34 which seats against the base of said slot, and said plate is also provided with depending lugs 35 which extend downwardly from edge 34 and embrace the side portions of the rod 17 at points below said transverse slot. The plate 33 is held rigidly in place in the upper end of rod 17 by the lugs 35, in conjunction with a transverse'pin 36 which passes through rod 17 and plate 33. The upper end of the plate 33 is provided with an upwardly extending car 37 which is located to electric switch which may be employed to make or break a circuit, or make andbreak a circuit for operating means, not shown, for

controlling combustion, or other means, for

example, a water supply valve for automatically supplying water to a boiler when the level drops below a determined point.

This switch may take a number of forms without departing from the scope of my invention, but in the preferred embodiment it includes a casing 40 supported upon the coupling 14 and having an opening 41 through which the upper end of the thrust member 39 projects. Within the casing 40 is a lever 42 fulcr'umed on the casing, as at 43, and carryin a socket member 44 in which engages the pointed upper end 39 of the thrust member 39, the arrangement being such that an upward movement of member 39 swings sald lever 42 upward on its fulcrum from the position shown in Fig. 1, in which the forward end of the lever is depressed below its fulcrum 43. On the opposite side of the lever 41 from the plunger 39, is a socket bearing 45 which receives a pin 46 carried by a spring plate or seat 47 which supports the lower end of a compression spring 48, the opposite end of which en ages a spring plate or seat 49. The

spring p ate or seat 49 is provided with a socket 50 in which is seated a polyfaced nut 51 threaded on an adjusting screw 52 which is fixed, as at 53, in the top wall of the casing 40 and extends axially of said spring 48. By adjusting the position of plate 49 on screw 52 the resistance of spring 48 to the thrust of element 39 may be regulated. The outer end of the lever 42 has pivotally connected hereto, as at 54, the lower end of a link 55, the upper end of which is pivoted, as at 56, to a 'tilting support 57'fi1lcrumed at 58 in any suitable manner in the casing. The support 57 is provided with spring clips 59 which support a switch member 60. This switch member is preferably in the form of an evacuated glass tube 60' provided with internal contacts 61 connected to circuit leads '62 in circuit with the device to be controlled (not shown); In the glass container 60 is a body of fluid-conducting material, for example,

mercury, which when the tube is tilted in one direction, for example, that shown in Fig. 1, immerses the contacts 61 and forms an electric circuit through said contacts, thereby completing the circuit through the leads 62 threaded bushing 65. Threaded in this bush-I ing and projecting forwardly of the transverse-arm 63 and lever 42, is a screw 64 which has a pointed end 70, preferably conical in form. At a point in the casing substantially diametrically opposite to the fulcrum 43, is a fixed pin 69. A differential spring 67 having cup shaped engaging or follower plates 66 and 68 is positioned between the screw 64 on lever 42 and pin 69, with the screw and the pin being seated respectively in the follower plates 66 and 68. The spring 67 when so positioned, normally tends to expand and exerts a downward component of force on the lever 42 in conjunction with the 'compression spring 48. The tension of the spring 67 may be varied so that it will exert the desired downward component of force by adjusting the screw 64 in its bushing 65.

A stop member 71 is fixed on the lever 42 and projects into the slot 72 in the casing 40 to limit the up and down movements of the lever 42.

This switch specifically forms the subject matter of my copending application, Serial N 0. 32,401, filed May 23, 1925, and it is therefore not believed necessary to describe the same in greater detail herein.

The device may operate by change of fluid pressure or bychange of water level or by change of both fluid pressure and water level acting in conjunction. Y

When the fluid pressure in, the chamber 2 and fitting 11 increases without any change in the vertical position of the float 26, as shown in Fig. 1, the pressure will act upon the diaphragm 28 and its head 20 to compress the diaphragm and raise the rod 17 with pin 16 riding in slot 18. The float 26 will remain in a substantially constant position so that as the rod 17 is raised, fixed points on the rod will move in arcs of concentric circles of which-a determinable point in the float 26 will be the common center. Therefore, the upper end of rod 17 will move in an arc and be rocked counter-clockwise and carry with it the lower end of thrust member 39, which will increase or straighten out the angle between rod 17 and member 39 and cause the erted by adjusting spring 48 and the down-j ward component of force exerted by differential spring 67 together oppose the upward movement of the bellows 28 and member 39. This differential spring 67 is so positioned, as above described with relation to lever 42, that any upward movement of the lever 42, though it compresses the spring 67, will nevertheless decrease the downward component or effective force exerted by spring 67 upon lever 42, due to the decrease in the angle of ap plication of the downward component caused by the movement of the lever 42. The spring 48 is so adjusted by means of nut 51, that its increased tension as the lever 42 is raised, and therefore its downward force, is less than the decrease in the downward component of force exerted by spring 67, and there is a consequent decrease in the combined downward force exerted by springs 48 and 67. This results in a snap or quick action being imparted to the .switch member 60, which is desirable for eflicient action of mercury tube switches. Movement of the bellows by force of fluid pressure existing in chamber 2 and fitting 11 is opposed or resisted by the combined downward force exerted by the springs 48 and 67 acting on and through lever 42, so that said bellows will not be collapsed by fluid pressure to operate the controller until the force exerted by the fluid pressure is suflicient to overcome the resistance of said springs. By suitable ad.- justment of said nut 51 and pin 64 the amount or degree of resistant force exerted by said springs may be regulated, set or determined to prevent actuation of the controller by fluid pressure onthe bellows until the force exerted by such fluid pressure reaches or builds up to a given or'desired point or value, whereupon any increase of such fluid pressure in the system will overcome the spring resistance and cause actuation of the controller. It will thus be seen that the device may be set to re. spond to a given fluid pressure condition within the limits of effective adjustment of the resistance afforded by said springs. The spring 7 48 is adjustable in conjunction with spring 67 to determine the point at which the lever 42 will start to respond to the fluid pressure on the bellows and the adjustment of the differential spring 67 determines the point at which the complete operation or movement of said lever 42 takes place in order to actuate the circuit controller.

When the water level in the chamber 2 drops, the float 26 will move downward with it from the position shown in Fig. 1. The float pivots upon the fulcrum 16 and transmits its movement to the rod 17 which will rotate about the pin 16 in a counter-clockwise direction. As the rod 17 rotates, it will carry with it the lower end of the member39 to effect a toggle action which will raise the member 39 and the lever 42 to compress the springs 48 and 67 and actuate the controlling device or switch 60. I

It is evident that-if a leak should occur in the boiler so that the water level dropped ra idly, and caused a sudden increase in t e steam pressure, that the thrust member 39 would be moved upward by the simultaneous lowering of the float 26 and increase in fluid pressure acting upon-the diaphragm or bellows 28 and sufiiclent to overcome the spring resistance, so that the switch member would be operated conjointly by the float and by the bellows.

What I claim and desire to secure by Letters Patent of the United States is 1. In a device of the character described, a casing having a float chamber, a float in said chamber and responsive to variation of liquid level therein, a controller, a lever having a connection with said controller to move the same, a pin supported at the end of said lever and extending lengthwise of said lever, means 'operatively connecting said float and said lever, fluid pressure-responsive means sealing said chamber and acting through said operating means to move said lever in one direction, a spring opposing said fluid-pressure means and operable to move said lever in the opposite direction, and a second spring opposing said fluid-pressure means when in one position and having a rocking support at one end and at its other end engagin said pin, said support being so arranged t at the resistance of the second spring is reduced when said operating means moves said lever.

2. In a device of the character described, a casing having a float chamber, a float in said chamber and responsive to variation of liquid level therein, a controller, a lever having a connection with said controller to move the same, means operativel connecting said float and said lever, flui pressure-responsive means sealing said chamber and acting through said operating means to move said lever in one direction, a spring opposing said fluid-pressure means and operable to move said lever in the opposite direction, and a second spring opposing said fluid pressure means when in one position and having a rocking support at one end and at its other end engaging said lever, said support being so arranged that the resistance of the second spring is reduced when said operating means moves said lever.

3. In a device of the character described, a casing having a float chamber, a float in said chamber and responsive to variation of liquid level therein, a controller, a lever having a connection with said controller to move the same, a pin supported at the end of said lever sealing said chamber and acting through said operating means to move said lever in one 'direction, and means engaging said pin to regulate action of said lever by said float and said pressure-responsive means.

4. In a device of the character described, the combination of a casing havin a float chamber, a float in said chamber an responsive to variation of liquid level therein, a controller, a lever having connection with the controller to move the same, means operatively connecting said float to said lever to move it in one direction, a spring opposing said float and operable to move said lever 1n the opposite direction, and a second spring opposing said float when in one position and having a rocking support at one end and at its other end engaging said lever, said support being so arranged that the resistance of the second spring is reduced when the said float acts to move said lever.

5. A device of the character described comprisin a float chamber, a float in said chamber an responsive to variation of liquid level therein, a controller, means for transmitting motion from said float to said controller to cause actuation of the controller, fluid pressure-responsive means sealing said last-named means to the chamber and responsive to fluid pressure in said chamber to actuate said cohtroller, resilient means resisting actuation of said controller by said pressure-responsive means, and means for setting the resistance of said resilient resisting means whereby said pressure-responsive means responds to a determined pressure condition in said chamber.

6. A device of the character described comprising a float chamber, afloat in said chamber and responsive to variation of liquid level therein, a controller, a lever connected to said controller to operate the controller, means for transmitting motion from said float to said lever, fluid pressure responsive means sealin said last-named means to the chamber an responsive to fluid pressure in said chamber said controller by said uid pressu're-respom' sive means, said last-named means being ad- 'ustable to set the point at which said controller is operated by said lever.

7. A device of the character described comprising a float ch amber havin a side opening, a substantially L-shaped ho ow fitting open at its ends, means securing said fitting to said chamber with one of said open ends in communication with said side opening, an annular plate secured and sealed to said fitting at the other of said open ends, a substantially cylindrical hollow expafisible-collapsible resilient corrugated member havin one end thereof sealed to said plate aroun the inner periphery thereof, a control means having a fulcrum support, a float in said chamber, a lever, means connecting said lever and said control means plunger means pivotally supported in sai float, said plunger means extending through the aperture of said annular plate and having engagement with said lever to move the same, and a head forsaid resilient corrugated member secured to said plunger means and sealing the free other end of said resilient corrugated member. a

8. In a device of the character described, a movable control device, resilient means exerting a force in opposition to movement'of said control device, the opposing force of said resilient means increasing upon movement of said control device, a second resilient means exerting a component of its force in opposition to movement of said control device, the

opposing component of force of said second 1,

resilient means decreasing upon movement of said control device, the opposing component of force decreasing at a greater rate than the increase of opposing force of said first resilient means whereby the combined opposing force of said first and said second resilient means decreases upon movement of said control device, and actuating means operative on and exerting a force to move said control device, the force exerted by said actuating means decreasing upon movement of said control device, the decrease in the combined opposing force of said first and said second resilient means being at a greater rate than the decrease of the force of said actuating means whereby said control device is moved quickly by said actuating means throughout its range of movement.

n a device of the character described, a I

movable control device, a float chamber, a float in said chamber operatively connected to said control device tomove the same, resilient means acting on said control device to exert a force to resist movement of said control device, by said float, the resisting force of said resilient means increasing upon movement of said control device by said float, and a second resilient means acting at an acute angle on said control device to exert a component of force to resist movement of said device by said float, the resisting com onent of force decreasing upon movement 0 said control device by said float, the resisting component of force decreasing at a greater rate than the increase of resisting force of said first resilient means, the force exerted by said float upon said control device decreasing upon movement of said float, the force exerted by said float decreasing at a less rate than the decrease of the combined resistance of said first and said second resilient means whereby said fioat moves said control device with a snap action through its range of movement.

In testimony whereof I have hereunto signed my name.

LEWIS W. EGGLESTON.

fitting and operable by said 

